The machining process for a wheel usually requires three-step machining. After the front, the rim, the center hole and other parts of the wheel are machined, bolt holes and a valve hole need to be machined in the third step, but due to the difference in the outer diameter and width of wheels and other parameters, it is difficult to machine different sizes of hubs with a set of fixture. In the actual machining process, whenever wheels of different sizes need to be replaced, a set of parts or even a complete set of fixture needs to be replaced, which increases the production assistance time of the workshop, reduces the production efficiency and increases the labor intensity of workers. If an automatic fixture adapting to different sizes of wheels can be researched and developed, the production efficiency is greatly improved.